1. Field of the Invention
The present invention generally relates to the field of coaxial connectors and more specifically to a coaxial connector assembly and an antenna assembly having a switching function, preferably used in a mobile phone.
2. Description of the Related Art
Coaxial connectors having a switching function are for example used in mobile phones to provide a connection option for an external antenna. When the external antenna is connected, an internal antenna of the mobile phone has to be disconnected from respective parts of the mobile phone.
Such a coaxial connector assembly for use in a mobile phone is known from WO 98/31078. FIG. 6 illustrates this prior art connector assembly in an unmated state thereof. The coaxial connector assembly comprises a first connector 1 and a second connector 2. The first connector 1 is mounted on a printed circuit board 5 within a device such as a portable phone having an outer housing 6 for reception in a device such as a telephone cradle 9. Furthermore, the second connector 2 is mounted within the telephone cradle 9 for mating with the first connector 1. Each connector comprises an inner contact 31, 21 surrounded by a respective outer contact 12, 22 being separated from its corresponding inner contact by a dielectric 13, 23. In the illustrated unmated state of the connector assembly a resilient contact arm 32 electrically connects the first and second surface mount contact portions 51 and 52. The inner contact 31 of the first connector 1 is moveable in an axial direction A. Upon mating of the first and second connector, the moveable inner contact 31 is depressed and separates the resilient contact arm 32 from a respective counter contact portion 53. Thereby a switching function is realised, wherein in a first state the first surface mount contact portion 51 and the second surface mount contact portion 52 are connected and in a second state separated from each other.
Furthermore, U.S. Pat. No. 5,625,177 describes a similar first connector which is mounted on a printed circuit board e.g. for testing parts of said printed circuit board when inserting a test probe having a second connector into the first connector. The second connector is of a coaxial type, having an inner conductor which protrudes in an axial (mating) direction and an outer conductor separated from the inner conductor by a dielectric. The first connector comprises a corresponding mating portion and a reversibly moveable spring arm abutting to a first contact portion electrically connected to a first portion of the printed circuit board. The spring arm further is electrically connected to a second portion of the printed circuit board. When the test probe connector is inserted in a direction perpendicular to the board, its protruding inner conductor depresses the spring arm. Thereby the contact between the spring arm and the first contact portion is separated and an electrical contact between the test probe connector and the spring arm is achieved.
During the mating or unmating process these connector assemblies are mechanically heavily stressed. In particular the printed circuit board and the electrical contacts thereto suffer from this mechanical influence.
Furthermore, in the example of the switched internal antenna, independently of the mating state of the assembly, the board is always electrically connected to the internal antenna providing a first RF-signal. As a consequence, when the external antenna in the mated state of the connector assembly provides a second RF-signal, internal antenna transmits unnecessarily its first RF-signal. Additionally, the printed circuit board has to be adapted to be able to provide and possibly shield the RF-signal on its provision from a corresponding interface portion of the board to the switching connector assembly mounted on the board.
The present invention has been made in consideration of the above disadvantages and has as its first object to provide a coaxial connector assembly with reduced complexity.
It is a second object of the present invention to provide an antenna assembly having a switching function, which is simple in its structure and may be manufactured with less parts and reduced costs.
It is still another object of the present invention to provide an antenna assembly and a coaxial connector assembly adapted to avoid mechanical stress for the printed circuit board and its contacts caused by the mating process.
To achieve these objects, according to a first aspect of the present invention there is provided a coaxial connector assembly comprising a first coaxial connector and a second coaxial connector matable therewith in an axial direction, each connector comprising a mating section having an inner contact surrounded by an outer contact and separated therefrom by a dielectric, the first or second coaxial connectors having a lead-in portion for guiding and locating the connector mating sections of the first and second coaxial connector during plugging together, wherein said inner contact is formed by a resilient metal strip which is integrally formed with a contact portion being adapted to provide a switchable electrical connection with a corresponding counter contact portion depending on the mated or unmated state of the coaxial connector assembly. Thereby the number of parts used in the first connector can be reduced and a corresponding assembly process becomes simplified.
In a preferred embodiment of the first aspect of the invention the inner contact of the resilient metal strip has a U-shaped form. This specific form stabilizes the resilient metal strip and additionally provides a rounded contact portion at its tip.
In a further preferred embodiment of the first aspect of the invention said resilient metal strip comprises a first contact leg having said contact portion arranged at its free end. By means of the first contact leg a small movement of the inner contact of said resilient metal strip may be transformed into a suitable movement of the contact portion of the resilient metal strip for separating same from the corresponding counter contact portion. Furthermore, the arrangement of the counter contact portion becomes more flexible by using the first contact leg.
In a preferred embodiment of the first aspect of the invention said resilient metal strip further comprises a second contact leg, having at its free end a second contact portion for providing an electrical connection to a printed circuit board (PCB). This form of an electrical contact is easy to manufacture and can be realised without soldering. Additionally, this structure can be realised without a corresponding mechanical connection to the board and thus allows to avoid the mechanical stress in the mating or unmating process.
An advantageous embodiment of the first aspect of the invention is achieved when each of said mating section of said first and second connector has a mating face opposing each other in the mated state of the connector assembly, wherein said metal strip extends in the axial direction through said first connector to protrude from the mating face thereof. Thereby a second connector without a protruding inner contact becomes suitable for use in the connector assembly.
A further advantageous embodiment of the first aspect of the invention is achieved when the inner contact of said second connector has a recess formed in its axial face to abut the tip of said protruding metal strip in the mated state of the connector assembly. Such a recess mechanically fixes said protruding metal strip in a radial direction.
According to a second aspect of the invention there is provided an antenna assembly having an integrated switching function, comprising a first coaxial connector being matable with a second coaxial connector in an axial direction, each connector comprising a mating section having an inner contact surrounded by an outer contact and separated therefrom by a dielectric, said first or second coaxial connectors having a lead-in portion for guiding and locating the connector mating sections of the first and second coaxial connector during plugging together, and switching means having a common RF input signal terminal and switching the RF signal to either an antenna portion of the assembly or said second connector depending on the unmated or mated state of the assembly, wherein said first coaxial connector is at least partially integrated with said antenna portion. Compared to the known connector assemblies, this antenna assembly having an integrated switching function provides a switched RF-signal. Hence, the RF-signal is only provided where needed and additional interface portions and transmission lines on a printed circuit board can be avoided. Furthermore, the compatibility and flexibility with respect to additional electrical units is improved.
In a preferred embodiment of the second aspect of the invention said inner contact is formed by a resilient metal strip which is integrally formed with a contact portion abutting to a contact of said antenna portion. Thereby the number of parts used in the assembly is further reduced.
An advantageous embodiment of the second aspect of the invention is achieved when said antenna portion and said first coaxial connector is formed by a single molded integrated device. Thereby, the number of parts used in the antenna assembly and its overall size is further reduced and its assembly process is simplified.
In a further preferred embodiment of the second aspect of the invention said resilient metal strip has a U-shaped form, for providing a stable inner contact and a rounded contact portion at its tip.
A further advantageous embodiment of the second aspect of the invention is achieved when said switching means comprises a first contact leg having said contact portion arranged at its free end. Thereby, the arrangement of the counter contact portion becomes flexible and moreover a small movement of said inner contact of said resilient metal strip can be transformed into a suitable movement of the contact portion arranged at the end of first contact leg.
In a further preferred embodiment of the second aspect of the invention said switching means comprises a second resilient contact leg, having at its free end said common RF signal terminal for providing an electrical connection to a printed circuit board (PCB). This electrical connection is flexible and can be realised without soldering. Additionally, it requires no corresponding mechanical connection to the board and thus allows to avoid the mechanical stress in the mating or unmating process.
In an advantageous preferred embodiment of the second aspect of the invention the second coaxial connector is connected to an external antenna, wherein the antenna portion forms an internal antenna. Thereby an internal antenna switching
Finally, according to a third aspect, the invention provides a telephone comprising a housing, a printed circuit board and a connector assembly according to the first aspect of the invention or an antenna assembly according to the second aspect of the invention, wherein said connector or antenna assembly and said printed circuit board are sustained by said housing.